I propose to conduct a series of experiments directed at identifying and systematically characterizing acoustically responsive regions of the human posterior lateral frontal lobe. This brain region is known to play an important role in receptive speech, and results of non-invasive imaging studies provide indirect evidence of frontal lobe activation during acoustic stimulation. Fundamental questions remain concerning the existence and extent of human frontal lobe auditory fields and their functional relationship to speech critical sites (e.g., Broca's area). These questions will be addressed directly using innovative neurosurgical experimental methods. My specific aims are to: 1) systematically map acoustically responsive regions of the frontal lobe; 2) characterize the physiologic response properties of these brain regions using acoustic stimuli of graded complexity, including speech sounds; 3) study the gross anatomical relationships between acoustically responsive sites and speech critical regions (as defined by electrical stimulation mapping); and 4) employ cortical cooling to examine the influence of local synaptic mechanisms on the observed experimental results.